Evaluate cot 12 cot 38 cot 52 cot 60 cot 78

Asked by sadhanapatil494 | 13th Jan, 2020, 08:02: PM

Expert Answer:

cot12° cot38° cot52° cot60° cot78°
= (cot12°× cot78°)(cot38° cot52°) cot60° 
=[cot12°×cot(90° - 12º)][cot38°×cot(90° - 38º) cot60° 
cot12°× tan12°× cot38°× tan38°× cot60° 
= 1 × 1× cot60° 
= 1/2

Answered by Yasmeen Khan | 14th Jan, 2020, 10:34: AM